Robotic harvesters may be the future

SALINAS, Calif. — A tight labor supply and the allure of savings motivate growers in the Salinas Valley as much as anywhere in California, but prospects for automating some field tasks may be brighter here because of the crop mix.

A ripe red strawberry shows up distinctly against its green background on any camera sensor that a robotic harvester, scaled up for commercial use, would rely on. Automated thinning and weeding of lettuce fields is already happening, though not everywhere.

“For a lot of the easier applications the technology is there, it’s the funding that will stop it,” Tony Koselka, founder of Vision Robotics Corp., said during a Western Growers Web seminar. “Other applications will get there in time.”

Robotic Harvesting LLC has tested a prototype strawberry harvester, partly funded by the California Strawberry Commission, in the Oxnard area. Agrobot, a Spanish company, is also eyeing the California market.

“The biggest barrier right now is a lack of investment,” he said. “Some of that investment needs to come from the growers, but some also needs to come from the U.S. government.”

Still, research done on robotics in the military, manufacturing and health care should pave a path for the produce industry, according to Koselka.

Thinning lettuce, pruning vines and other tasks may be automated rather easily. The real challenge is harvesting a delicate plant or piece of fruit.

“We’ve developed a special gripper for grasping strawberries so there’s no damage to the fruit,” Wickham said.

A commercial version of that strawberry harvester — which requires a skilled operator — would cost around $300,000. Net labor savings, he said, would be close to $1.1 million over five years — for eight rows and eight pickers per shift. Most growers, though, have larger operations and would spend as well as save more.

“Our machines pick at a rate of every 4 to 5 seconds,” Wickham said. “Some say human pickers can pick faster. The machine picks slower, but you still save money because it’s cheaper.”

Yields on lettuce are up about 2% to 3% for users of Vision Robotics lettuce thinners, Koselka said. Payback on initial investment is one to two years, he estimates, for a thinner in the field four to six months of the year.

The thinning is done by spray, replacing hoeing or other spray methods.

“Growers used to hoeing who go out and see a stand done with a mechanized thinner are amazed at how much more uniform the lettuce is,” Koselka said.

There are prospects for further yield gains on lettuce.

“Because the crop is more uniform, growers are starting to tighten it up,” Koselka said. “Instead of 10-inch spacing, going to 9 inches can improve yield a fair amount.”

Ramsay Highlander Inc. has offered a lettuce thinner for about four years. The company is in beta testing in Europe on a robotic lettuce picker, Frank Maconachy, president and chief executive officer, told growers at the March 26 Western Growers Web seminar.